Dynamo-electric machine.



A. M. GRAY. DYNAMO ELEGTILIG MACHTNE. unmmxon FILED 0011a, 1910.

Patented June 25,

UNITED STATES PATENT OFFICE.

aLnxannEn GRAY, or MILWAUKEE, WISCONSIN, ASSIGNOR 'ro COMPANY, A CORPORATION or NEW JERSEY.

ALLrs cHALMERs DYNAMIC-ELECTRIC MACHINE.

.'Specification of Letters Patent.

Patented Juries 5, 1912.

Application filed October 8, 1910. Serial No. 585,93l).

To allvwhom it may concern Be it known that I, ALEXANDER M. Gr er, a subject of the ,King of England, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements 1n DynamdElectric Machines, of which the "usually act at that time as an induction motor. In order to facilitate its action as an induction motor, conducting rods transverse .both tothe magnetic lines of force and to the direction of relative movement be:

tween the armature and field member have been embedded in the field;poles near their surfaces,.the correspondingends of .the rods in the several poles be'ing interconnected;

Thus .a structure resemblin the rotor ofa squirrel cage motor is. obtained. These in- 1 terconnected rods also serve as dampers to prevent hunting after the machine has at tained synchronous speed. In order to pre-' vent losses while the machine is operating under normal conditions, it is'necessary that the damper rods in any pole be spaced apart circumferentially a distance equal to, or an exact multiple of, the distance between two adjacent slots in the armature core as otherwise there would always be heavfi currents circulating in the rods and their end connections. Heretofore, the spacing of the rods has been symmetrical in each pole and the. same in all poles. With this construction, the rods in all the poles come opposite slots in the armature core simultaneously. As a result, there are certain dead points from which the motor will not start.

It is the object of my present invention to avoid these dead points, while at the same time retaining the advantages of preventing heavy currents durlng normal 0 oration. To do this, the .rods in the, fie d poles are spaced so that-while the rods in any one pole all come opposite armature slots at the same time, the rods in all the poles will not do obtaining this result is by spacing the rods in the poles dissymmetrically with res t tothe center lines of the poles with vw 'ch hub, and main arms 14.

so. A preferredway of they are respectively, associated; the dissymmetry in adjacent poles ispreferably equal and opposite. i

The various novel features of my invention will be apparentfrom'the description and drawings, and will. be particularly pointed out in the claims. ,T Figure 1 is a partly sectionall'side elevation of a fragment of a dyna'mo electr'io machine embodying my invention; and Fig. 2 is a section on the=,line.2--2 ofEig. 1.; The synchronous ldyhar'norigdeetric machinehere illustrated is of thesnotating field type, though my inventionfisinotu limited thereto.

The stator or armature comprises the usual slotted core lo windings 11 em-' bedded in thesldtdthe whole being support-'- poles mounted duaq fim il3, which in turn is supported usual ,maimm; by; 8 Sh ft f e' p l 16, and L7 are illustrated; flihe'field' poles may have. t l1e-. usual field -18.' Extending through each poleat lright angles both to the: magnetic lines of; ioree and the direction of relative .movementjbe ween-field and armature members, 'andal'soat right angles .to, the laminations of the cores if these be laminated, are several conducting rods 19. Corresponding ends-of all the rods on eachpole, and preferablyiof all the'rods; on all the poles, are interconnected. .';I-h1s interconnecting can be accomplished in' any desired manner, the arrangement illustrated for doing it being'a preferred o merely. As illustrated, at each sideof eachfield ole 'is a casting 20 having aflat portibnlw. ich

bears a ainst' the laminae'of-the poles and toqwhic the rods .19 areriveted or' otherwisefastened, another flat portion which overlaps the-outerlendsofthe field coils 18 to protect them from being-thrown outward by centrifugal force,anda1flange portion' which extends 'inw-ariparallelto the field coils and towhich a 'llllg 21 may be fastened,- as by means of .bolts 22, The flat portion over the rend-of the field eoilamay extend over the ring 21 to help hold the latter against the action of centrifugalforce; The two flat portions. are preferablyponnected by strengthening mbsg T-he, roasts;

' uer lines-.of such p'oles, also ings 20 connect the corresponding ends of the rods 19 in the same pole, and the rings 21, which may be sectional if desired, con nect corresponding ends of rods in different poles.

The gist of my invention lies in the spacing of the rods 19. These are so spaced that the rods onany one pole, say on the pole 15, all come opposite slots in the armature at the "same time, but the rods on different poles, as on 15 and 16, come opposite slots in the armature at different times. Preferably when the rods 19 on the pole 15 are opposite slots, the rods 19 on the pole 16 are opposite teeth, as illustrated. In order for all the rods on one pole to come opposite slots at the same time, it is necessary that the "rods on such pole be spaced apart distances equal to, or exact multiples of, the

distance betweenadjacent armature slots,

as shown; they are spaced apart a distance equal to" twice such distance. This prevents losses when-the machine is operating at synchronous sf eed, 'the rods then serving as dampers? 'Ehere are various ways for causinglthe rods 19 on difi'erent poles not to come opposite armature slots at the same time, hut-thatil1ustrated is new deemed preferable. Here the rodson each poleare dissymmetrically spaced, the rods on adjacent poles'being-dissymmetrically spaced equally in o positedirections so that the same punc ings and castings can be used for all poles though in reverse positions on alternate poles. The rods 19 on the pole 16, for instance, while spaced apart distances equal tofltw-icc that between adjacent armature slots, are all somewhat to the right of the positions they would occupy if symmetrically :spaeed with reference. to the center line o.Ttlie'pole,-preferably by a distance iequal to 'one-fourth Qthat between adjacent armature slots. .Those on poles 15 and 17 are also spaced apart among themselves in the same iway, but arat'o the left, of the 0- sitions they would occupy if symmetrica lly spaced-with reference to the respective cenreferably by a distance equal to one-fourtii that between adjacentz'armature slots. Thus when the rods 19 on the poles15 and 17 are opposite slotsfthose on thepol'e's 16 are'opposite armature teeth. With this arrangement there are no dead points, so that the motor can he started from whatever position in which it may happen *to stop. Many modifications maybe made in the precise arrangement shown and described, and I aim in myclaims to cover all such modifications which do not involve a departure from the spirit and scope of my invention.

What I claim as new is:

1. A synchronous dynamo-electric machine comprising an armature having a slotted core, a field member, and eo nduct in rods fixed relatively to the field member an having their corresponding ends interconnee-ted, the rods being spaced in groups so that a plurality of groups less than the whole number of groups each have rods all of which simultaneously come opposite armature slots. p

2. A synchronous dynamo-electric machine comprising an armature having a slotted core,a field member having field poles, con-- ducting rods extending through each field pole transverse to the plane of rotation, and means for interconnecting eorres ending ends of said rods, the rods in each p0 e being aced so that they come opposite armature s ots simultaneously and those in some les dose at differenttlmes from those in ot ers.

3. A synchronous dynamo-electric machine comprising an armature having a slotted core, a field member, and conducting rods extending transversely through the field member and having their corresponding ends interconnected, the rods being arranged in groups so that the rods in each group all come op osite armature slots simultaneously while t ose in adjacent groups do so dis-simultaneously.

4. A synchronous dynamorlectricmachine comprising an armature havin a slotted core, a field member having eld poles, and conducting rods extending trans versely through the field poles and having their corresponding ends interconnected, the rods in. each field pole being spaced apart so that they come opposite armature slots at thesame time and the rods in adjacent field poles come opposite armature slots at different times. p

A synchronous dynamo-electric machine comprising an armature, a fieldmemher having field poles," and conducting rods extendingtransversely through each field pole and having theircorrcsponding ends miter-connected, rods in each pole being spaced dissyunnetrically with respect to the center line of such pole.

6. A synchronous dynamo-electric machine comprisingan armature, a field mems her having projecting field poles, and con ducting rods extending transversely through the field poles and having their correspondiug ends interconnected, said rods in each pole being spaced dissymmetrically with respect to the center line of such pole and the dissymmctry in adjacent poles being equal and opposite.

7. A synchronous dynamo-electric machine comprisin an armature havin a slotted core, a eld member havingeld poles and conducting rods extending transversely through each field pole and having their corresponding ends interconnected, the

conducting rods on each field pole being spaced symmetrically with respect to a ceri center tain line and so that they all come opposite armature slots at the same time and those on adjacent poles are spaced so that when the rods on one pole are opposite-armature slots those of the poles adjacent thereto are opposite armature teeth.

8* A 'ncnronous dynamo-electric ma.- chine comprising an armature having a siotted core, a field member having field poles, and conducting rods extending transversely through said field poles and having their cor esponding ends interconnected, the rods on each pole being spaced symmetrically with respect to a line parallel to the line ofthe pole and at a distance tl'iereirom equal to one-fourth the distance between adjacent armature slots.

9. A synchronous dynamo-electricmachine comprising an armature having a slotted core, a field member having field poles and conducting rods extending transversely through said field poles and having their corresponding ends interconnected, the rode on each pole being spaced symmetrically with respect to a line parallel to the center line of the pole and at a distance therefrom equal to one-fourth the distance between adjacent armature slots, such center lines of symmetry on alternate poles being on opposite sides of. the center lines of the poles. I

10. A synchronous dynamo-electric ma chine comprising an armature, a field member having field poles, qhnducting rods extending transversely through said field poles and having their ends interconnected, the mechanical arrangement of the rods on one pole being diiferent li-om that of those on another but the number of rods on each pole being the same.

11. A synchronous dynamo-electric machine comprising an armature, a field member, conducting rods arranged in groups and extending transversely through the field member, and means for interconnecting corresponding ends of said rods, the spacing between some of the groups being different from that between others.

Milwaukee, Wis, Sept. 5, 1910.-- In testimony whereof I aflix my signature, in the presence of two witnesses.

i ALEXANDE M. GRAY.

l/Vitnesses t G. B. Scrum, CHAS. L. BYRON. 

